Forouzan QandA

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1. There are ______________ Internet service providers.There are ______________ Internet service providers. A)

A) regionalregional B)

B) locallocal C)

C) national and internationalnational and international D)

D) all of the aboveall of the above 2.

2. ______ refers to ______ refers to the physical or logical arrangement the physical or logical arrangement of a network.of a network. A)

A) TopologyTopology B)

B) Mode of operationMode of operation C)

C) Data flowData flow D)

D) None of the aboveNone of the above 3.

3. A ______ is a data communication system spanning states, countries, or the whole world.A ______ is a data communication system spanning states, countries, or the whole world. A) A) MANMAN B) B) WANWAN C) C) LANLAN D)

D) none of the abovenone of the above 4.

4. A _______ connection provides a dedicated link between two devices.A _______ connection provides a dedicated link between two devices. A) A) primaryprimary B) B) multipointmultipoint C) C) point-to-pointpoint-to-point D) D) secondarysecondary 5.

5. Which topology requires a multipoint connection?Which topology requires a multipoint connection? A) A) BusBus B) B) StarStar C) C) MeshMesh D) D) RingRing 6.

6. A ________ is a set of rules thaA ________ is a set of rules tha t governs data communication.t governs data communication. A) A) protocolprotocol B) B) forumforum C) C) standardstandard D)

7. In a ______ connection, two and only two devices are connected by a dedicated link.In a ______ connection, two and only two devices are connected by a dedicated link. A)

A) multipointmultipoint B)

B) point-to-pointpoint-to-point C)

C) (a) and (b)(a) and (b) D)

8. The information to be communicated in a The information to be communicated in a data communications system is the _______.data communications system is the _______. A) A) MediumMedium B) B) ProtocolProtocol C) C) MessageMessage D) D) TransmissionTransmission 9.

9. ________ defines ________ defines how a particular pattern to be how a particular pattern to be interpreted, and what action interpreted, and what action is to be taken based is to be taken based on thaton that interpretation. interpretation. A) A) SyntaxSyntax B) B) SemanticsSemantics C) C) TimingTiming D)

10. Frequency of failure and network recovery time after a failure are measures of the _______of a network.Frequency of failure and network recovery time after a failure are measures of the _______of a network. A) A) PerformancePerformance B) B) SecuritySecurity C) C) ReliabilityReliability D) D) FeasibilityFeasibility 11.

11. A television broadcast is an example of A television broadcast is an example of _______ transmission._______ transmission. A)

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B) B) simplexsimplex C) C) full-duplexfull-duplex D) D) automaticautomatic 12.

12. Data flow between two devices can occur in a _______ way.Data flow between two devices can occur in a _______ way. A) A) simplexsimplex B) B) half-duplexhalf-duplex C) C) full-duplexfull-duplex D)

13. _______ are special-interes _______ are special-interest groups that quickly test, evaluatet groups that quickly test, evaluate, and standardize new technologies., and standardize new technologies. A)

A) Standards organizationsStandards organizations B)

B) Regulatory agenciesRegulatory agencies C)

C) ForumsForums D)

D) All of the aboveAll of the above 14.

14. Which agency developed standards for physical connection interfaces andWhich agency developed standards for physical connection interfaces and electronic signaling specifications?

electronic signaling specifications? A) A) ISOISO B) B) ITU-TITU-T C) C) ANSIANSI D) D) EIAEIA 15.

15. A _______ is a data communication system A _______ is a data communication system within a building, plant, owithin a building, plant, o r campus, or between nearbyr campus, or between nearby buildings. buildings. A) A) LANLAN B) B) MANMAN C) C) WANWAN D)

16. _______ refers _______ refers to two characteristics: when to two characteristics: when data should be sent and how data should be sent and how fast it can be sent.fast it can be sent. A) A) SemanticsSemantics B) B) TimingTiming C) C) SyntaxSyntax D)

17. This was the first network.This was the first network. A) A) CSNETCSNET B) B) NSFNETNSFNET C) C) ARPANETARPANET D) D) ANSNETANSNET 18.

18. Devices may be arranged in a _____ topology.Devices may be arranged in a _____ topology. A) A) meshmesh B) B) ringring C) C) busbus D)

19. _______ is the _______ is the protocol suite for the current protocol suite for the current Internet.Internet. A) A) UNIXUNIX B) B) NCPNCP C) C) TCP/IPTCP/IP D) D) ACMACM 20.

20. ________ is a colle ________ is a collection of many separate networks.ction of many separate networks. A) A) A WANA WAN B) B) An internetAn internet C) C) A LANA LAN D)

21. In a ________ connection, three or more devices share a In a ________ connection, three or more devices share a link.link. A)

A) point-to-pointpoint-to-point B)

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C)

C) (a) and (b)(a) and (b) D)

22. Which organization has authority over interstate and international commerce in the Which organization has authority over interstate and international commerce in the communicationscommunications field? field? A) A) FCCFCC B) B) IEEEIEEE C) C) ITU-TITU-T D) D) ISOCISOC 23.

23. In the original ARPANET, _______ were directly connected together.In the original ARPANET, _______ were directly connected together. A)

A) routersrouters B)

B) host computershost computers C)

C) networksnetworks D)

D) IMPsIMPs 24.

24. Communication between a computer and a keyboard involves ______________ transmission.Communication between a computer and a keyboard involves ______________ transmission. A) A) simplexsimplex B) B) half-duplexhalf-duplex C) C) full-duplexfull-duplex D) D) ; automatic; automatic 25.

25. Which topology requires a central controller or hub?Which topology requires a central controller or hub? A) A) MeshMesh B) B) BusBus C) C) StarStar D) D) RingRing 26.

26. The _______ is the physical path over which a The _______ is the physical path over which a message travels.message travels. A) A) ProtocolProtocol B) B) SignalSignal C) C) MediumMedium D)

D) All the aboveAll the above 27.

27. In a _______ connection, more than two devices can share a single link.In a _______ connection, more than two devices can share a single link. A) A) multipointmultipoint B) B) point-to-pointpoint-to-point C) C) primaryprimary D) D) secondarysecondary 28.

28. _______ refers _______ refers to the structure or forto the structure or format of the data, meaning the ordemat of the data, meaning the order in which they are presented.r in which they are presented. A) A) SemanticsSemantics B) B) SyntaxSyntax C) C) TimingTiming D)

D) All of the aboveAll of the above 29.

29. An unauthorized user is a network _______ issue.An unauthorized user is a network _______ issue. A) A) SecuritySecurity B) B) ReliabilityReliability C) C) PerformancePerformance D)

30. ________ is an idea or ________ is an idea or concept that is a precursconcept that is a precursor to an Internet standard.or to an Internet standard. A) A) RCFRCF B) B) IDID C) C) RFCRFC D)

31. In _______ transmission, the channel capacity is shared by both communicating devices at all times.In _______ transmission, the channel capacity is shared by both communicating devices at all times. A) A) simplexsimplex B) B) half-duplexhalf-duplex C) C) full-duplexfull-duplex D) D) half-simplexhalf-simplex

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32. The ______ layer adds a header to The ______ layer adds a header to the packet coming from the upper the packet coming from the upper layer that includes the logicallayer that includes the logical addresses of the sender and receiver.

addresses of the sender and receiver. A)

A) data linkdata link B)

B) networknetwork C)

C) physicalphysical D)

33. Which of the following is an application layer service?Which of the following is an application layer service? A)

A) File transfer and accessFile transfer and access B)

B) Mail serviceMail service C)

C) Remote log-inRemote log-in D)

34. When data are transmitted from device A to device B, the header from A's layer 4 is read by B's _______When data are transmitted from device A to device B, the header from A's layer 4 is read by B's _______ layer. layer. A) A) TransportTransport B) B) ApplicationApplication C) C) PhysicalPhysical D)

35. __________ pro __________ provides full transport layer services vides full transport layer services to applications.to applications. A) A) UDPUDP B) B) TCPTCP C) C) ARPARP D)

36. The process-to-process delivery of the entire message is the responsibility of the The process-to-process delivery of the entire message is the responsibility of the _______ layer._______ layer. A) A) TransportTransport B) B) ApplicationApplication C) C) PhysicalPhysical D) D) NetworkNetwork 37.

37. The ______ layer is responsible for moving frames from one hop (node) to the next.The ______ layer is responsible for moving frames from one hop (node) to the next. A)

A) transporttransport B)

B) data linkdata link C)

C) physicalphysical D)

38. The _______ layer is responsible for delivering data units from one The _______ layer is responsible for delivering data units from one station to the next without errors.station to the next without errors. A)

A) physicalphysical B)

B) data linkdata link C)

C) transporttransport D)

D) networknetwork 39.

39. The session, presentation, and application layers are the ____ support layersThe session, presentation, and application layers are the ____ support layers .. A)

A) useruser B)

B) networknetwork C)

C) both (a) and (b)both (a) and (b) D)

D) neither (a) nor (b)neither (a) nor (b) 40.

40. The physical, data link, and network layers are the ______ support layers.The physical, data link, and network layers are the ______ support layers. A)

A) networknetwork B)

B) useruser C)

C) both (a) and (b)both (a) and (b) D)

D) neither (a) nor (b)neither (a) nor (b) 41.

41. The ________ layer is responsible for the process-to-process delivery of The ________ layer is responsible for the process-to-process delivery of the entire message.the entire message. A) A) transporttransport B) B) physicalphysical C) C) networknetwork

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D) data link

42. The _______ layer lies between the network layer and the a pplication layer. A) Data link

B) Transport C) Physical

D) None of the above

43. The Internetworking Protocol (IP) is a _ _______ protocol. A) connection-oriented

B) reliable C) both a and b D) none of the above

44. The _______ layer links the network support layers and the user support layers. A) session B) transport C) data link D) network 45. ICMPv6 includes _______. A) IGMP B) ARP C) RARP D) a and b

46. The ____ address uniquely defines a host on the Internet. A) IP

B) port C) specific D) physical

47. The _______ layer coordinates the functions required to transmit a bit stream over a physical medium. A) data link

B) transport C) network D) physical

48. The ______ layer is responsible for the source-to-destination delivery of a packet across multiple network links.

A) network B) physical C) data link D) transport

49. Mail services are available to network users through the _______ layer. A) Transport

B) Physical C) Data link D) Application

50. The ____ created a model called the Open Sy stems Interconnection, which allows diverse systems to communicate.

A) IEEE B) ISO C) OSI

D) none of the above

51. The _______ layer changes bits into electromagnetic signals. A) Physical

B) Transport C) Data link

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52. IPv6 has _______ -bit addresses. A) 128

B) 32 C) 64 D) variable

53. The_____ address identifies a process on a host. A) specific

B) port C) IP D) physical

54. The_________ layer is responsible for the delivery of a message f rom one process to another. A) transport

B) network C) physical

55. The _________ layer enables the users to access the network. A) application

B) physical C) data link D) transport

56. The TCP/IP _______ layer is equivalent to the combined session, presentation, and application layers of the OSI model.

A) data link B) network C) physical D) application

57. When a host on network A sends a message to a host on network B, which address does the router look at?

A) logical B) physical C) port

58. As the data packet moves from the upper to the lower layers, headers are _______. A) Rearranged

B) Removed C) Added D) Modified

59. The physical layer is concerned with the movement of _______ over the physical medium. A) dialogs

B) protocols C) bits D) programs

60. To deliver a message to the correct application program running on a host, the _______ address must be consulted.

A) physical B) port C) IP

61. Ethernet uses a ______ physical address that is imprinted on the network interface card (NIC). A) 32-bit

B) 6-byte C) 64-bit

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62. The _______ layer is the layer closest to the transmission medium. A) Network

B) Transport C) Physical D) Data link

63. The OSI model consists of _______ layers. A) eight

B) seven C) five D) three

64. The ________ address, also known as the link address, is the address of a node as defined by its LAN or WAN.

A) IP B) port C) specific D) physical

65. Layer 2 lies between the physical layer and the _______ layer. A) Data link

B) Transport C) Network

66. Why was the OSI model developed?

A) The rate of data transfer was increasing exponentially

B) Standards were needed to allow any two systems to communicate C) Manufacturers disliked the TCP/IP protocol suite.

67. In the OSI model, as a data packet moves from the lower to the upper layers, headers are _______. A) removed

B) added C) rearranged D) modified

68. In the OSI model, when data is transmitted from device A to device B, the header from A's layer 5 is read by B's _______ layer.

A) session B) physical C) transport D) presentation

69. The seven-layer _____ model provides guidelines for the development of universally compatible networking protocols.

A)ISO B)OSI C)IEEE

70. The Internet model consists of _______ layers. A)Eight

B)Seven C)Five D) Three

71. In the OSI model, what is the main function of the transport layer? A) process-to-process message delivery

B)node-to-node delivery C)synchronization

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72. _______ is a process-to-process protocol that adds only port addresses, checksum error control, and length information to the data from the upper layer.

A)IP B)TCP C)UDP

73. The ______ layer establishes, maintains, and synchronizes the interactions between communicating devices.

A) session B) physical C) transport D) network

74. A port address in TCP/IP is ______ bits long. A) 16

B) 32 C) 48

75. In the OSI model, encryption and decryption are functions of the ________ layer. A) application

B) presentation C) session D) transport

76. TCP/IP is a ______ hierarchical protocol suite developed ____ the OSI model. A) five-layer; before

B) six-layer; before C) seven-layer; before D) five-layer; after

77. The ________ address, also known as the link address, is the address of a node as defined by its LAN or WAN.

A) logical B) port C) physical

78. The _______ model shows how the network functions of a computer ought to be organized. A) ANSI

B) CCITT C) ISO D) OSI

79. The _______ layer ensures interoperability between communicating devices through transformation of data into a mutually agreed upon format.

A) network B) presentation C) transport D) data link

80. If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ________ V. A) 2

B) 1 C) -2

D) between -2 and 2 81. _________ can impair a signal.

A) Noise B) Attenuation C) Distortion

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D) All of the above

82. ________is the rate of change with respect to time. A) Time

B) Frequency C) Amplitude D) Voltage

83. A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means ________.

A) P2 equals P1 B) P2 is zero

C) P2 is much larger than P1 D) P2 is much smaller than P1

84. Baseband transmission of a digital signal is possible only if we have a ____ channel. A) bandpass

B) low-pass C) high rate D) low rate

85. ________ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium.

A) Distortion B) Attenuation C) Noise D) Decibel

86. A sine wave in the ______ domain ca n be represented by one single spike in the _____ d omain. A) time; phase

B) frequency; time C) time; frequency D) phase; time

87. If the bandwidth of a signal is 5 KHz and the lowest frequency is 52 K Hz, what is the highest frequency? A) 5 KHz

B) 47 KHz C) 57 KHz D) 10 KHz

88. In a time-domain plot, the horizontal axis is a measure of ________. A) phase

B) signal amplitude C) frequency D) time

89. _______ data are continuous and take continuous values. A) digital

B) analog C) a or b

90. Frequency and period are ______. A) proportional to each other B) inverse of each other C) the same

91. When propagation speed is multiplied by propagation time, we get the ________. A) wavelength of the signal

B) throughput

C) distance a signal or bit has traveled D) distortion factor

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92. A _________ sine wave is not useful in data communications; we need to send a _______ signal. A) single-frequency; composite

B) composite; single-frequency This is the correct answer. C) single-frequency; double-frequency

93. The _________ product defines the number of bits that can fill the link. A) delay-amplitude

B) frequency-amplitude C) bandwidth-period D) bandwidth-delay

94. _______ signals can have only a limited number of values. A) Digital

B) Analog C) A or B

95. Before data can be transmitted, they must be transformed to ________. A) periodic signals

B) electromagnetic signals C) aperiodic signals

D) low-frequency sine waves 96. Data can be ________.

A) digital B) analog C) A or B

97. ________ is a type of transmission impairment in which the signal loses strength due to the different propagation speeds of each frequency that makes up the signal.

A) Noise B) Distortion C) Attenuation D) Decibel 98. Signals can be ________. A) digital B) analog C) either (a) or (b) D) neither (a) nor (b) 99. A sine wave is ________.

A) periodic and discrete B) aperiodic and discrete C) periodic and continuous D) aperiodic and continuous

100. _______ data have discrete states and take discrete values. A) Analog

B) Digital C) A or B

101. For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate. A) noiseless

B) noisy C) low-pass D) bandpass

102. What is the bandwidth of a signal that ranges from 1 MHz to 4 MHz? A) 1 KHz

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B) 3 MHz C) 4 MHz

103. _____ signals can have an infinite number of values in a range. A) Analog

B) Digital C) A or B

104. A(n)_________ signal is a composite analog signal with an infinite bandwidth. A) digital

B) analog

C) either (a) or (b) D) neither (a) nor (b)

105.A periodic signal completes one cycle in 0.001 s. What is the frequency? A) 1 Hz

B) 100 Hz C) 1 KHz D) 1 MHz

106.The _____ of a composite signal is the difference between the highest and the lowest frequencies contained in that signal.

A) period B) bandwidth C) frequency D) amplitude

107. ________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal.

A) Noise B) Distortion C) Attenuation D) Decibel

108. _______ describes the position of the waveform relative to time 0. A) Amplitude

B) Phase C) Frequency D) Voltage

109.Given two sine waves A and B, if the frequency of A is twice that of B, then the period of B is ________ that of A.

A) one-half B) twice C) the same as

D) indeterminate from

110.As frequency increases, the period ________. A) increases

B) decreases C) doubles

D) remains the same

111.If the available channel is a ____ channel, we cannot send a digital signal directly to the channel. A) low-pass

B) low rate C) bandpass D) high rate

112.For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate. A) low-pass

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B) bandpass C) noisy D) noiseless

113. In a frequency-domain plot, the horizontal axis measures the ________. A) phase

B) frequency C) slope

D) peak amplitude

114.Which of the following encoding methods does not provide for synchronization? A) RZ

B) NRZ-L C) NRZ-I D) Manchester

115.If the frequency spectrum of a signal has a bandwidth of 500 Hz with the highest frequency at 600 Hz, what should be the sampling rate, according to the Nyquist theorem?

A) 200 samples/s B) 500 samples/s C) 1000 samples/s D) 1200 samples/s

116. In asynchronous transmission, the gap time between bytes is _ ______. A) variable

B) fixed C) zero

D) a function of the data rate

117. ______ substitutes eight consecutive zeros with 000VB0VB. A) B4B8

B) B8ZS C) HDB3

118.The most common technique to change an a nalog signal to digital data is called __________. A) sampling

B) PAL C) PCM

119.The minimum bandwidth of Manchester and differential Manchester is ____ that of NRZ. A) the same as

B) twice C) thrice

120. The signal rate is sometimes called the ____ rate. A) bit

B) baud C) signal

121. Unipolar, bipolar, and polar encoding are types of _______ encoding. A) line

B) block C) NRZ

D) Manchester

122. ________ is normally referred to as mB/nB coding; it replaces each m-bit group with an n-bit group. A) Line coding

B) Block coding C) Scrambling

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123. In ______ schemes, the voltages are on the both sides of the time axis. For example, the voltage level for 0 can be positive and the voltage level for 1 can be negative.

A) unipolar B) bipolar C) polar

D) all of the above

124. The ________ rate defines the number of data elements sent in 1s; the ______ rate is the number of signal elements sent in 1s.

A) signal; data B) data; signal C) baud; bit

125. The idea of RZ and the idea of NRZ-L are combined into the ________ scheme. A) Manchester

B) differential Manchester C) both (a) and (b)

D) neither (a) nor (b)

126. ________ provides synchronization without increasing the number of bits. A) Line coding

127. The Nyquist theorem specifies the minimum sampling rate to be_______. A) equal to the lowest frequency of a signal

B) equal to the highest frequency of a signal C) twice the bandwidth of a signal

D) twice the highest frequency of a signal 128. PCM is an example of _______ conversion.

A) analog-to-analog B) analog-to-digital C) digital-to-digital D) digital-to-analog

129. There are three sampling methods: __________. A) ideal, natural, and flat-top

B) ideal, sampled, and flat-top C) quantized, sampled, and ideal D) none of the above

130. In _______encoding, we use three levels: positive, zero, and negative. A) unipolar

B) polar C) bipolar

131. Block coding can help in _______ at the receiver. A) Synchronization

B) Error detection C) Attenuation D) (a) and (b)

132. In Manchester and differential Manchester encoding, the transition at the middle of the bit is used for A) bit transfer

B) synchronization C) baud transfer D) none of the above

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133. _______ encoding has a transition at the beginning of each 0 bit. A) Differential Manchester

B) Manchester C) RZ

D) All the above

134. In ______, the change or lack of change in the level of the voltage determines the value of the bit. A) NRZ-L

B) NRZ-I

C) both (a) and (b) D) neither (a) nor (b)

135. In ___________ there is always a transition at the middle of the bit, but the bit values are determined at the beginning of the bit. If the next bit is 0, there is a transition; if the next bit is 1, there is none.

A) Manchester

136. In _______ encoding, the duration of the bit is divided into two halves. The voltage remains at one level during the first half and moves to the other level in the second half. The transition at the middle of the bit provides synchronization.

A) Manchester

137. The ________ mode provides synchronization for the entire stream of bits must. In other words, it guarantees that the data arrive at a fixed rate.

A) isochronous B) synchronous C) asynchronous D) none of the above

138. The idea of RZ and the idea of NRZ-I are combined into the ________ scheme. A) Manchester

139. In decoding a digital signal, the receiver calculates a running average of the received signal power, called the _______.

A) base B) line C) baseline

140. In _________ transmission, we send bits one after another without start or stop bits or gaps. It is the responsibility of the receiver to group the bits.

A) synchronous B) asynchronous C) isochronous D) none of the above

141. ______ finds the value of the signal amplitude for each sample; ____ finds the change from the previous sample.

A) DM; CM B) DM; PCM C) PCM; DM

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A) HDB3 B) B4B8 C) B8ZSf

143. The ______ scheme uses three levels (+V, 0, and -V) and three transition rules to move between the levels.

A) 4B5B B) MLT-3 C) 2B1Q

144. While there is (are) only _____ way(s) to send parallel data, there is (are) _____ subclass(es) of serial transmission.

A) one; two B) one; three C) two; three

145. Which quantization level results in a more faithful reproduction of the signal? A) 2

B) 8 C) 16 D) 32

146. A _________ digital signal includes timing information in the data being transmitted. A) self-synchronizing

B) self-transmitted C) self-modulated D) none of the above

147. In _______ transmission, bits are transmitted over a single wire, one at a time. A) asynchronous serial

B) synchronous serial C) parallel

D) (a) and (b)

148. The first step in PCM is ________. A) quantization

B) sampling C) modulation

149. _______ encoding has a transition at the middle of each bit. A) Manchester

B) Differential Manchester C) RZ

D) All the above

150. In ______ transmission, we send 1 start bit (0) at the beginning and 1 or more stop bits (1s) at the end of each byte.

A) synchronous B) asynchronous C) isochronous D) none of the above

151. In _______ transmission, bits are transmitted simultaneously, each across its own wire. A) Asynchronous serial

B) Synchronous serial C) Parallel

D) (a) and (b)

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A) AMI B) RZ C) NRZ-I D) Manchester

153. The data rate is sometimes called the ___ rate. A) bit

B) baud C) signal

154. _______ provides redundancy to ensure synchronization and inherent error detection. A) Line coding

155. In _______ transmission, a start bit and a stop bit frame a character byte. A) synchronous serial

B) asynchronous serial C) parallel

D) (a) and (b)

156. Two common scrambling techniques are ________. A) B8ZS and HDB3

B) AMI and NRZ C) NRZ and RZ

D) Manchester and differential Manchester

157. ___________ conversion involves three techniques: line coding, block coding, and scrambling. A) Analog-to-analog

B) Analog-to-digital C) Digital-to-analog D) Digital-to-digital

158. The _____ scheme uses data patterns of size 2 and encodes the 2-bit patterns as one signal element belonging to a four-level signal.

A) MLT-3 B) 4B5B C) 2B1Q

159. In _____, the level of the voltage determines the value of the bit. A) NRZ-I

B) NRZ-L

C) both (a) and (b) D) neither (a) nor (b)

160. ________ is the process of converting digital data to a digital signal. A) Line coding

161. In a _____ scheme, all the signal levels are on one side of the time axis, either above or below. A) unipolar

B) polar C) bipolar

D) all of the above

1. In ________, the amplitude of the carrier signal is varied to create signal elements. Both fre quency and phase remain constant

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A) PSK B) ASK C) FSK D) QAM

163.How many carrier frequencies are used in BPSK? A) 0

B) 1 C) 2

164.The constellation diagram of 16-QAM has ______ dots. A) 4

B) 8 C) 16

165.AM and FM are examples of ________ conversion. A) analog-to-analog

B) digital-to-digital C) analog-to-digital D) digital-to-analog

166.The Federal Communications Commission (FCC) allows ______ kHz for each FM station. A) 20

B) 100 C) 200

167.Analog-to-analog conversion is needed if the available bandwidth is _______. A) band-pass

B) low-pass C) either (a) or (b) D) neither (a) nor (b)

168.In _____ transmission, the frequency of the carrier signal is modulated to follow the changing voltage level (amplitude) of the modulating signal. The peak amplitude and phase of the ca rrier signal remain constant, but as the amplitude of the information signal changes, the frequency of the carrier changes correspondingly.

A) AM B) FM C) PM

169.How many carrier frequencies are used in QPSK? A) 0

B) 2 C) 1

170.Which of the following is not a digital-to-analog conversion? A) FSK

B) ASK C) AM D) PSK

171. _______ conversion is the process of changing one of the characteristics of an analog signal based on the information in the digital data.

A) Analog-to-analog B) Digital-to-digital C) Digital-to-analog D) Analog-to-digital

(19)

172.If the baud rate is 400 for a QPSK signal, the bit rate is ________ bps. A) 100

B) 400 C) 800 D) 1600

173.In ________, the phase of the carrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant.

A) PSK B) FSK C) ASK D) QAM

174.Which of the following is not an analog-to-analog conversion? A) QAM

B) AM C) PM D) FM

175.How many carrier frequencies are used in BASK? A) 0

B) 1 C) 2

176.Quadrature amplitude modulation (QAM) is a combination of ___________. A) PSK and FSK

B) ASK and FSK C) ASK and PSK D) none of the above

177.In _________, the frequency of the carrier signal is varied to represent data. Both peak amplitude and phase remain constant.

A) ASK B) FSK C) PSK D) QAM

178.If the bit rate for an ASK signal is 1200 bps, the baud rate is ________. A) 1200

B) 600 C) 400 D) 300

179.The constellation diagram of BPSK has ______ dots. A) 0

B) 1 C) 2

180.The constellation diagram of QPSK has ______ dots. A) 4

B) 2 C) 1

181.In _______, the peak amplitude of one signal level is 0; the other is the same as the amplitude of the carrier frequency.

A) OOK B) PSK C) FSK

(20)

182.If the bit rate for a 16-QAM signal is 4000 bps, what is the baud rate? A) 1200

B) 1000 C) 400 D) 300

183.ASK, PSK, FSK, and QAM are examples of ________ conversion. A) analog-to-analog

B) digital-to-digital C) analog-to-digital D) digital-to-analog

184.If the bit rate for an FSK signal is 1200 bps, the baud rate is ________. A) 1200

B) 600 C) 400 D) 300

185.The constellation diagram of BASK has ______ dots. A) 0

B) 1 C) 2

186.The Federal Communications Commission (FCC) allows ______kHz for each AM station. A) 20

B) 10 C) 5

187.How many carrier frequencies are used in BFSK? A) 2

B) 1 C) 0

188.In _____ transmission, the phase of the carrier signal is modulated to follow the changing voltage l evel (amplitude) of the modulating signal.

A) AM B) FM C) PM

189. _________ conversion is the representation of analog information by an analog signal. A) Analog-to-analog

B) Digital-to-digital C) Analog-to-digital D) Digital-to-analog

190.In _____ transmission, the carrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal.

A) PM B) FM C) AM

191.In QAM, both ________ of a carrier frequency are varied. A) phase and frequency

B) amplitude and phase C) frequency and amplitude D) none of the above

(21)

A) QAM B) ASK C) FSK D) PSK

193.Given an AM radio signal with a bandwidth of 10 KHz and the highest-frequency component at 705 KHz, what is the frequency of the carrier signal?

A) 710 KHz B) 705 KHz C) 700 KHz

D) Cannot be determined from given information

194.A constellation diagram shows us the __________ of a signal element, particularly when we are using two carriers (one in-phase and one quadrature).

A) amplitude and frequency B) amplitude and phase C) frequency and phase D) none of the above

195.If the baud rate for a 64-QAM signal is 2000, what is the bit rate? A) 12000

B) 1000 C) 400 D) 300

196.The _______ technique uses M different carrier frequencies that are modulated by the source signal. At one moment, the sign modulates one carrier frequency; at the next moment, the signal modulates another carrier frequency.

A) DSSS B) FHSS C) FDM D) TDM

197.In synchronous TDM, for n signal sources of the same data rate, each frame contains _______ slots. A) n + 1

B) n - 1 C) 0 to n D) n

198.Which multiplexing technique transmits digital signals? A) WDM

B) FDM C) TDM

199.The sharing of a medium and its link by two or more devices is called _______. A) modulation

B) multiplexing C) encoding D) line discipline

200. _______ is designed to be used in wireless applications in which stations must be able to share the

medium without interception by an eavesdropper and without being subject to jamming from a malicious intruder.

A) Multiplexing B) Spread spectrum C) Modulation

D) None of the above.

201. ______ is an analog multiplexing technique to combine optical signals. A) WDM

(22)

C) TDM

D) None of the above 202.FDM is an _________technique.

A) digital B) analog

C) either (a) or (b) D) none of the above

203. ______ can be applied when the bandwidth of a link (in hertz) is greater than the combined bandwidths of the signals to be transmitted.

A) TDM B) FDM

C) Both (a) or (b) D) Neither (a) or (b)

204.In TDM, the transmission rate of the multiplexed path is usually _______ the sum of the transmission rates of the signal sources.

A) equal to B) less than C) greater than D) not related to

205.In a multiplexed system, __ lines share the bandwidth of ____ link. A) 1; n

B) n; 1 C) 1; 1 D) n; n

206. _________ utilization is the use of available bandwidth to achieve specific goals. A) Amplitude

B) Frequency C) Bandwidth

207. ____ is designed to use the high bandwidth capability of fiber-optic cable. A) WDM

B) FDM C) TDM

208.We can divide ____ into two different schemes: synchronous or statistical. A) WDM

B) TDM C) FDM

209.In ________ TDM, each input connection has an allotment in the output even if it is not sending data. A) isochronous

B) statistical C) synchronous D) none of the above

210.In ________ TDM, slots are dynamically allocated to improve bandwidth efficiency. A) isochronous

B) synchronous C) statistical

211.The word ______ refers to the portion of a _______ that carries a transmission. A) line; channel

B) channel; link C) link; channel

(23)

D) line; link

212.Which multiplexing technique shifts each signal to a different carrier frequency? A) FDM

B) TDM

C) Both (a) and (b) D) None of the above

213.Which multiplexing technique transmits analog signals? A) WDM

B) TDM C) FDM D) (a) and (c)

214. ________ is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link.

A) Demodulating B) Multiplexing C) Compressing D) None of the above

215. ________ can be achieved by using multiplexing; ______ can be achieved by using spreading. A) Privacy and antijamming; efficiency

B) Privacy and efficiency; antijamming C) Efficiency; privacy and antijamming D) Efficiency and antijamming; privacy

216.The ______ technique expands the bandwidth of a signal by replacing each data bit with n bits. A) DSSS

B) FHSS C) FDM D) TDM

217. ________ is a digital process that allows several connections to share the high bandwidth of a link. A) WDM

B) TDM C) FDM

218. _______ is a digital multiplexing technique for combining several low-rate channels into one high-rate one.

A) WDM B) TDM C) FDM

219.In ________, we combine signals from diff erent sources to fit into a la rger bandwidth. A) line coding

B) block coding C) spread spectrum D) none of the above

220.Which multiplexing technique involves signals composed of light beams? A) WDM

B) FDM C) TDM

221.When the angle of incidence is _______ the critical angle, the light beam bends along the interface. A) less than

B) equal to C) more than

(24)

222.Transmission media lie below the _______ layer. A) application

B) transport C) network D) physical

223. _________ cable consists of an inner copper core and a second conducting outer sheath. A) Twisted-pair

B) Shielded twisted-pair C) Coaxial

D) Fiber-optic

224. __________ consists of a central conductor and a shield. A) Twisted-pair

B) Coaxial C) Fiber-optic

225. _______ cable can carry signals of higher frequency ranges than _______ cable. A) Coaxial; twisted-pair

B) Twisted-pair; fiber-optic C) Coaxial; fiber-optic D) none of the above

226. _________ are used for cellular phone, satellite, and wireless LAN communications. A) Radio waves

B) Infrared waves C) Microwaves D) none of the above

227.The inner core of an optical fiber is _______ in composition. A) copper

B) glass or plastic C) bimetallic D) liquid

228.What is the major factor that makes coaxial cable less susceptible to noise than twisted-pair cable? A) insulating material

B) inner conductor C) diameter of cable D) outer conductor

229.Signals with a frequency below 2 MHz use _______ propagation. A) line-of-sight

B) sky C) ground

230.In an optical fiber, the inner core is _______ the cladding. A) less dense than

B) denser than

C) the same density as D) another name for

231. ________ cable consists of two insulated copper wires twisted together. A) Twisted-pair

232.In fiber optics, the signal is _______ waves. A) radio

(25)

C) infrared

D) very low-frequency

233.Signals with a frequency above 30 MHz use _______propagation. A) line-of-sight

B) sky C) ground

234.A parabolic dish antenna is a(n) _______ antenna. A) unidirectional

B) bidirectional C) omnidirectional D) horn

235.A(n) _______ medium provides a physical conduit from one device to another. A) unguided

B) guided

C) either (a) or (b) D) none of the above

236. ________ cable is used for voice and data communications. A) Twisted-pair

237.Signals with a frequency between 2 MHz an d 30 MHz use _______ propagation. A) ground

B) line-of-sight C) sky

238.Transmission media are usually categorized as _______. A) determinate or indeterminate

B) fixed or unfixed C) guided or unguided D) metallic or nonmetallic

239. ________ are used for short-range communications such as those between a PC and a peripheral device. A) Radio waves

B) Infrared waves C) Microwaves D) none of the above

240. _________ media transport electromagnetic waves without the use of a physical conductor. A) Guided

B) Unguided C) Either (a) or (b) D) None of the above

241. ________ cables are composed of a glass or plastic inner core surrounded by cladding, all encased in an outside jacket.

A) Twisted-pair B) Coaxial C) Fiber-optic

242.Which of the following primarily uses guided media? A) radio broadcasting

B) satellite communications C) local telephone system D) cellular telephone system

(26)

243.When a beam of light travels through media of two different densities, if the angle of incidence is greater than the critical angle, _______ occurs.

A) refraction B) reflection C) criticism D) incidence

244.Which of the following is not a guided medium? A) fiber-optic cable B) coaxial cable C) twisted-pair cable D) atmosphere 245.Microwaves are _________. A) omnidirectional B) bidirectional C) unidirectional D) none of the above

246. ________ cables carry data signals in the form of light. A) Twisted-pair

D) none of the above 247.Radio waves are _________.

A) unidirectional B) omnidirectional C) bidirectional D) none of the above

248.In a fiber-optic cable, the signal is propagated along the inner core by _______. A) refraction

B) reflection C) modulation

249.Packet-switched networks can also be divided into ______subcategories: virtual-circuit networks and datagram networks.

A) five B) three C) two D) four

250.In __________, each packet is treated independently of all others. A) circuit switching

B) datagram switching C) frame switching D) none of the above

251.Based on the Clos criteria, if N = 200, then k must be equal to or greater than ______. A) 19

B) 21 C) 31 D) 41

252.In _________, resources are allocated on demand. A) circuit switching

(27)

A) time-division B) two-dimensional C) space-division D) three-dimensional

254.In a ________ network, two types of addressing are involved: global and local. A) datagram

B) virtual-circuit C) circuit-switched D) none of the above

255.In a three-stage space division switch, if N = 200, the number of crosspoints is ______. A) 40,000

B) less than 40,000 C) greater than 40,000 D) greater than 100,000

256.A ________ network is made of a set of switches connected by physical links, in which each link is divided into n channels.

A) circuit-switched B) line-switched C) frame-switched D) none of the above

257.In a banyan switch, for 8 inputs and 8 outputs, we have _____ microswitches at each stage. A) 2

B) 3 C) 4 D) 8

258.In _________, there is no resource allocation for a packet. A) circuit switching

259.A _________ network is a cross between a circuit -switched network and a datagram network. It has some characteristics of both.

A) packet-switched B) frame-switched C) virtual-circuit D) none of the above

260.The most popular technology in time-division switching is c alled the _________. A) TSI

B) STI C) ITS

261.A switched WAN is normally implemented as a _______ network. A) virtual-circuit

B) datagram C) circuit-switched D) none of the above

262.We can say that a packet switch has _______ types of components. A) four

B) three C) two

263.In a one-stage space division switch, if N = 200, the number of crosspoints is ______. A) 20,000

(28)

B) 40,000 C) 30,000 D) 10,000

264.In a banyan switch, for 8 inputs and 8 outputs, we have _____ stages. A) 2

B) 3 C) 4 D) 8

265.A switch in a datagram network uses a routing table that is based on the ______ address. A) destination

B) source C) local

266.Traditionally, _____ methods of switching have been important. A) six

B) five C) four D) three

267.The network layer in the Internet is designed as a __________ network. A) circuit-switched

B) datagram C) virtual-circuit D) none of the above

268.A ________ switch combines space-division and time-division technologies to take advan tage of the best of both.

A) SSS B) TST C) TTT

269.In _______, the resources need to be reserved during the setup phase; the resources remain dedicated for the entire duration of data transfer phase until the teardown phase.

A) frame switching B) datagram switching C) circuit switching D) none of the above

270.Based on the Clos criteria, if N = 200, then n must be equal to or greater than ____. A) 40

B) 30 C) 20 D) 10

271.Circuit switching takes place at the ________ layer. A) physical

B) data line C) network D) transport

272.A ________ switch combines crossbar switches in several (normally three) stages. A) multiple path

B) multiple crossbar C) multistage

273.In _______ there are no setup or teardown phases. A) circuit switching

(29)

C) frame switching D) none of the above

274.We can divide today's networks into ____ broad categories. A) five

B) four C) three D) two

275.A ________ switch is a multistage switch with microswitches at each stage that route the packets based on the output port represented as a binary string.

A) TSI B) banyan C) crossbar

276.The _______ address in the header of a packet in a datagram network normally remains the same during the entire journey of the packet.

A) destination B) source C) local

277.Based on the Clos criteria, if N = 200, then the minimum number of crosspoints is greater than or equal to _______.

A) 42,000 B) 20,000 C) 18,000 D) 15,200

278.The simplest type of switching fabric is the ______ switch. A) crossbar

B) crosspoint C) TSI

D) STS

279.To use a cable network for data transmission, we need two key devices: a ______ and a _________ A) CT; CMTS

B) CM; CMTS C) CM; CMS

280.A local telephone network is an example of a _______ network. A) packet-switched

B) message-switched C) circuit-switched D) none of the above

281.A traditional cable TV network transmits signals ______. A) downstream

B) upstream

C) upstream and downstream D) none of the above

282.The traditional cable TV system used ________cable end to end. A) twisted-pair

B) fiber-optic C) coaxial

283.The telephone network is made of ______ major components. A) 4

(30)

C) 2

284.Data from a computer are _______; the local loop handles _______ signals. A) analog; analog

B) digital; digital C) digital; analog D) analog; digital

285.The original telephone network, which is referred to as the plain old telephone system (POTS), was an ________ system.

A) analog B) digital

C) digital as well as analog D) none of the above

286.The protocol that is used for signaling in the telephone network is called ______. A) SSS

B) SS7 C) POP

287. _______technology is a set of technologies developed by the telephone companies to provide high data rate transmission.

A) LDS B) ASL C) DSL

288.The local loop has _______ cable that connects the subscriber telephone to the nearest end office. A) fiber-optic

B) coaxial C) twisted-pair D) none of the above

289.The second generation of cable networks is call ed a(n) _________ network. A) HCF

B) HFC C) CFH

290.The largest portion of the bandwidth for ADSL carries _______. A) upstream data

B) downstream data C) control data

D) voice communication

291. _______ is suitable for businesses that require comparable upstream and downstream data rates. A) SDSL

B) ADSL C) VDSL D) (b) and (c)

292.The carrier that handles intra-LATA services is called a (n) _____ . A) IXC

B) LEC C) POP

293.DMT is a modulation technique that combines elements o f _______ and _______. A) FDM; QAM

B) FDM; TDM C) PSK; FSK

(31)

D) QDM; QAM

294.The carrier that handles inter-LATA services is called a (n) _______. A) IXC

B) LEC C) POP

295.The modern telephone network is now ________. A) digital

B) digital as well as analog C) analog

296.In an HFC network, the upstream data are modulated using the _______ modulation technique. A) ASK

B) PCM C) QAM D) QPSK

297. _______ was designed as an alternative to the T-1 line. A) ADSL

B) HDSL C) VDSL D) SDSL

298.HDSL encodes data using _______. A) 2B1Q

B) 1B2Q C) 4B/5B D) 6B/8T

299.In an HFC network, the downstream data are modulated using the _______ modulation technique. A) PCM

B) QAM C) PSK D) ASK

300.Another name for the cable TV offic e is the _______. A) head end

B) combiner C) fiber node D) splitter

301.The term modem is a composite word that refers to the two functional entities that make up the device: a signal _______ and a signal _______.

A) demodulator; modulator B) modulator; demodulator C) modern; demo

302.The two most common digital services are ________ service and ______. A) switched/56; DDS

B) switched/56; switched/64 C) DDS; switched 64

D) leased; out-of-band

303.The United States is divided into many _______. A) IXCs

B) LECs C) LATAs

(32)

A) ADSL B) CMTS C) DOCSIS D) MCNS

305.In ________signaling, a portion of the bandwidth is used for signaling and another portion for data. A) mixed

B) in-band C) out-of-band D) none of the above

306.Telephone companies provide two types of analog services: analog _______ services and analog _____services.

A) leased; out-of-band B) out-of-band; in-band C) switched; in-band D) switched; leased

307.The HFC network uses _______ cable. A) coaxial

B) twisted-pair C) fiber-optic

D) a combination of (a) and (c)

308.In ______signaling, the same circuit is used for both signaling and data. A) mixed

B) out-of-band C) in-band

309.Most popular modems available are based on the ________standards. A) X-series

B) V-series C) VX-series

310.Checksums use _________ arithmetic. A) one's complement arithmetic B) two's complement arithmetic C) either (a) or (b)

311.The checksum of 1111 and 1111 is _________. A) 0000

B) 1111 C) 1110 D) 0111

312.In modulo-11 arithmetic, we use only the integers in the range ______, inclusive. A) 1 to 10

B) 0 to 10 C) 1 to 11

313.In cyclic redundancy checking, the divisor is _______ the CRC. A) one bit less than

B) one bit more than C) The same size as D) none of the above

314.The ________ between two words is the number of differences between corresponding bits. A) Hamming rule

(33)

C) Hamming distance D) none of the above

315.The _______ of a polynomial is the highest power in the polynomial. A) range

B) power C) degree

316.In modulo-2 arithmetic, __________ give the same results. A) addition and subtraction

B) addition and multiplication C) addition and division D) none of the above

317.In cyclic redundancy checking, what is the CRC? A) The quotient

B) The dividend C) The divisor D) The remainder

318.Which error detection method consists of just one redundant bit per data unit? A) CRC

B) Checksum

C) Simple parity check

D) Two-dimensional parity check

319.In _____ coding, we divide our message into blocks, each of k bits, called ___. A) block; blockwords

B) block; datawords C) linear; datawords D) none of the above

320.A _____ error means that two or more bits in the data unit have changed. A) burst

B) double-bit C) single-bit

321.Adding 1 and 1 in modulo-2 arithmetic results in _________. A) 0

B) 1 C) 2

322.In ________ error correction, the receiver corrects errors without requesting retransmission. A) onward

B) forward C) backward

323.If the Hamming distance between a dataword and the corresponding codeword is three, there are _____ bits in error.

A) 5 B) 4 C) 3

324.A simple parity-check code can detect __________ errors. A) an odd-number of

B) an even-number of C) two

(34)

325.The Hamming distance between equal codewords is _________. A) 0

B) 1 C) n

326.In a linear block code, the _______ of any two valid codewords creates another valid codeword. A) ANDing

B) XORing C) ORing

327.In ________ error correction, the receiver asks the sender to send the da ta again. A) forward

B) backward C) retransmission D) none of the above

328.We can divide coding schemes into two b road categories: ________ and ______coding. A) linear; nonlinear

B) block; convolution C) block; linear

329.In modulo-2 arithmetic, we use only ______. A) 1 and 2

B) 0 and 1 C) 0 and 2

330.To guarantee correction of up to 5 errors in all cases, the minimum Hamming distance in a block code must be ________.

A) 11 B) 6 C) 5

331.The _____of errors is more difficult than the ______. A) detection; correction

B) correction; detection C) creation; correction D) creation; detection

332.In block coding, if k =2 and n =3, we have _______ invalid codewords. A) 4

B) 8 C) 2

333.The checksum of 0000 and 0000 is __________. A) 0000

B) 1111 C) 0111 D) 1110

334.In one's complement arithmetic, if positive 7 is 0111, then negative 7 is ________. A) 1101

B) 1000 C) 1111

335.In block coding, if n = 5, the maximum Hamming distance between two codewords is ________. A) 5

(35)

B) 3 C) 2

336.Which error detection method uses one's complement arithmetic? A) Checksum

B) CRC

C) Simple parity check

D) Two-dimensional parity check

337.The divisor in a cyclic code is normally called the _________. A) redundancy

B) degree C) generator

338.In modulo-2 arithmetic, we use the ______ operation for bo th addition and subtraction. A) OR

B) XOR C) AND

339.We add r redundant bits to each block to make the length n = k + r. The resulting n-bit blocks are called _________.

A) codewords B) datawords C) blockwords

340.To guarantee the detection of up to 5 errors in all cases, the minimum Hamming distance in a block code must be _______.

A) 11 B) 5 C) 6

341.A generator that contains a factor of ____ can detect all odd-numbered errors. A) x

B) 1 C) x + 1

342. _______codes are special linear block codes with one extra property. If a codeword is rotated, the result is another codeword.

A) Convolution B) Cyclic C) Non-linear

343.The Hamming distance between 100 and 001 is ________. A) 0

B) 1 C) 2

344.In Go-Back-N ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the receive window must be _____.

A) 1 B) 15 C) 16 D) 31

(36)

345.In Go-Back-N ARQ, if frames 4, 5, and 6 are received successfully, the receiver may send an ACK _______ to the sender.

A) 6 B) 7 C) 5

D) any of the above

346.The Stop-And-Wait ARQ, Go-Back-N ARQ, and the Selective Repeat ARQ are for ______ channels. A) noiseless

B) noisy

347.The _________Protocol, adds a simple error control mechanism to the _______Protocol. A) Selective Repeat ARQ; Go-Back-N ARQ

B) Go-Back-N ARQ; Stop-and-Wait C) Stop-and-Wait ARQ; Stop-and-Wait D) none of the above

348.In PPP, the ________ is responsible for establishing, maintaining, configuring, and terminating links. A) PAP

B) CHAP C) LCP D) NCP

349.HDLC is an acronym for _______.

A) Half-duplex digital link combination B) Host double-level circuit

C) High-duplex line communication D) High-level data link control

350.In Selective Repeat ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the receive window must be _____.

A) 1 B) 15 C) 16 D) 31

351.In Go-Back-N ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the send window must be _____.

A) 1 B) 15 C) 16 D) 31

352.In Stop-and-Wait ARQ, the a cknowledgment number always announces in ______ arithmetic the sequence number of the next frame expected.

A) modulo-m B) modulo-2 C) modulo-4

353.In Selective Repeat ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the send window must be _____.

A) 1 B) 15 C) 16 D) 31

354. _______ control refers to a set of procedures used to restrict the amount of data that the sender can send before waiting for acknowledgment.

(37)

B) Error

C) Transmission D) none of the above

355.In the Go-Back-N Protocol, if the size of the sequence number field is 8, the sequence numbers are in ________ arithmetic,

A) modulo-256 B) modulo- 8 C) modulo-2

356. ______ control refers to methods of error detection and correction. A) Flow

B) Error

357.In a Go-Back-N ARQ, if the window size is 63, what is the range of sequence numbers? A) 1 to 63

B) 1 to 64 C) 0 to 63 D) 0 to 64

358.Both Go-Back-N and Selective-Repeat Protocols use a _________. A) sliding window

B) sliding frame C) sliding packet D) none of the above

359.In _________, the configuration is balanced. The link is point-to-point, and each station can function as a primary and a secondary.

A) ARM B) ABM C) NBM D) NRM

360.Byte stuffing means adding a special by te to the data section of the frame when there is a character with the same pattern as the ______.

A) trailer B) flag C) header

361.The ______ Protocol has neither flow nor error control. A) Selective-Repeat ARQ

B) Go-Back-N ARQ C) Stop-and-Wait D) Simplest

362.The most common protocol for point-to-point access is the Point-to-Point Protocol (PPP), which is a _________protocol.

A) byte-oriented B) bit-oriented

C) character-oriented D) none of the above

363.For Stop-and-Wait ARQ, for 10 data packets sent, _______ acknowledgments are needed. A) less than 10

B) more than 10 C) exactly 10

(38)

A) Standard B) Fixed-size C) Variable-size D) None of the above

365. _______ control refers to a set of procedures used to restrict the amount of data that the sender can send before waiting for acknowledgment.

A) Flow B) Error

366.In a ________ protocol, the data section of a frame is a sequence of characters. A) bit-oriented

B) character-oriented C) either (a) or (b) D) none of the above

367.In _______ framing, there is no need f or defining the boundaries of frames. A) standard

B) fixed-size C) variable-size D) none of the above

368.The _______Protocol has both flow control and error control. A) Stop-and-Wait

B) Selective-Repeat ARQ C) Go-Back-N ARQ D) both (b) and (c)

369.In _________, the station configuration is unbalanced. We have one primary station and multiple secondary stations.

A) ARM B) NBM C) NRM D) ABM

370.In a _________ protocol, the data section of a frame is a sequence of bits. A) bit-oriented

B) byte-oriented C) either (a) or (b) D) none of the above

371.In ________ framing, we need a delimiter (flag) to define the boundary of two frames. A) standard

B) fixed-size C) variable-size D) none of the above

372.High-level Data Link Control (HDLC) is a _______ protocol for communication over point-to-point and multipoint links.

A) byte-oriented B) bit-oriented C) character-oriented D) none of the above

373.Bit stuffing means adding an extra 0 to the data section of the frame when there is a sequence of bits with the same pattern as the ________.

A) trailer B) flag C) header

(39)

374.In the _________Protocol, if no acknowledgment for a fram e has arrived, we resend all outstanding frames.

A) Go-Back-N ARQ B) Selective-Repeat ARQ C) Stop-and-Wait ARQ D) none of the above

375.The Simplest Protocol and the Stop-and-Wait Protocol are for ______ channels. A) noiseless

B) noisy

376.The _______Protocol has flow control, but not error control. A) Selective-Repeat ARQ

B) Stop-and-Wait C) Simplest

D) Go-Back-N ARQ

377.In Stop-and-Wait ARQ, we use sequence numbers to number the frames. The sequence numbers are based on __________arithmetic.

A) modulo-m B) modulo-2 C) modulo-4

378.In the _____ Protocol, the sender sends its frames one after another with no regard to the receiver. A) Simplest

B) Selective-Repeat ARQ C) Stop-and-Wait

D) Go-Back-N ARQ

379. _________control in the data link layer is based on automatic repeat request, which is the retransmission of data.

A) Flow B) Error

380.In PPP, _______ is a three-way hand-shaking authentication protocol in which th e password is kept secret; it is never sent online.

A) PAP B) LCP C) NCP D) CHAP

381.In PPP, ________ is a simple a uthentication procedure with a two-step process: A) CHAP

B) PAP C) LCP D) NCP

382.In the _________ protocol we avoid unnecessary transmission by sending only frames that are corrupted. A) Selective-Repeat ARQ

B) Stop-and-Wait ARQ C) Go-Back-N ARQ D) none of the above

383.In ________ protocols, we use ________. A) byte-oriented; bit stuffing

B) bit-oriented; bit stuffing C) character-oriented; bit stuffing

(40)

384.In the _____ Protocol, the sender sends one frame, stops until it receives confirmation from the receiver, and then sends the next frame.

A) Simplest B) Stop-and-Wait C) Selective-Repeat ARQ D) Go-Back-N ARQ

385.Stop-and-Wait ARQ is a special case of Go-Back-N ARQ in which the size of the send window is ___. A) 1

B) 2 C) 8

D) none of the above 386.ARQ stands for _______.

A) Acknowledge repeat request B) Automatic retransmission request C) Automatic repeat quantization D) Automatic repeat request

387. _______ in the data link layer separates a message from one source to a destination, or from other messages going from other sources to other destinations.

A) Controlling B) Framing C) Digitizing

388.Data link control deals with the design a nd procedures for ______ communication. A) node-to-node

B) process-to-process C) host-to-host D) none of the above

389.In _________ protocols, we use ________. A) bit-oriented; character stuffing B) character-oriented; bit stuffing C) character-oriented; byte stuffing D) none of the above